•Hierarchical N-doped porous carbon was cost-efficiently synthesized from cellulose.•The doping N can be easily tunable, and has a remarkable impact on porous carbon.•The doping N can significantly improve the supercapacitance of porous carbon.Producing hierarchical porous N-doped carbon from renewable biomass is an essential and sustainable way for future electrochemical energy storage. Herein we cost-efficiently synthesized N-doped porous carbon from renewable cellulose by using urea as a low-cost N source, without any activation process. The as-prepared N-doped porous carbon (N-doped PC) had a hierarchical porous structure with abundant macropores, mesopores and micropores. The doping N resulted in more disordered structure, and the doping N content in N-doped PC could be easily tunable (0.68–7.64%). The doping N functionalities could significantly improve the supercapacitance of porous carbon, and even a little amount of doping N (e.g. 0.68%) could remarkably improve the supercapacitance. The as-prepared N-doped PC with a specific surface area of 471.7 m2 g−1 exhibited a high specific capacitance of 193 F g−1 and a better rate capability, as well as an outstanding cycling stability with a capacitance retention of 107% after 5000 cycles. Moreover, the N-doped porous carbon had a high energy density of 17.1 W h kg−1 at a power density of 400 W kg−1.

•A novel lignin-based bio-adsorbent for Pb(II) adsorption was developed.•The maximum adsorption capacity for Pb(II) reached to 130.2 mg/g.•The maximum removal efficiency for low concentration of Pb(II) was 100%.•The lignin-based bio-adsorbent presented outstanding cycling capability.The removal of heavy metals ions from wastewater by an economic, high-effective, and environmentally friendly method is particularly important. In this study, an effective lignin-based bio-adsorbent (SAPL-1.5), which contained specific functional groups and spatial cross-linking structures, was synthesized through chemical modification. SAPL-1.5 was comprehensively characterized by 31P, 1H, 13C NMR, and elemental analysis as compared to the raw lignin. The results showed that the chemical reactivity of lignin was significantly improved after phenolation process, and the adsorption groups were successfully grafted onto lignin macromolecule. In addition, the influences of pH, SAPL-1.5 dosage, contact time, and initial Pb (II) concentration on the adsorption performance was systematically investigated. The highest adsorption capacity reached to 130.2 mg/g (Pb (II), 140 mg/L), and a removal efficiency of 100% was achieved (Pb (II), 20 mg/L). Moreover, the adsorption isotherm and adsorption kinetics indicated that the results were fitting well with the Langmuir and pseudo-second-order model, respectively. Furthermore, the removal efficiency of SAPL-1.5 for Pb (II) (20 mg/mL) still maintained over 85% after 5 cycles. Therefore, the lignin-based material obtained could be considered as a promising potential adsorbent with a low cost, high performance and reutilization for its application in the wastewater treatment process. It is believed that the lignin-based bio-sorbent can enlarge the lignin valorization in the current biorefinery process.

•Cellulose materials were esterified with a fast transesterification method.•CA fibers were prepared by a simple and rapid process.•The obtained CA was analyzed by XRD, FT-IR, 1H, 13C and HSQC NMR.•The property of CA solutions and CA fibers were affected by cellulose's DP.Transesterification is a mild process to prepare cellulose acetate (CA) as compared with the traditional method. In this study, CA fibers were produced from six cellulose raw materials based on a simple and rapid transesterification method. The properties of the CA solutions and the obtained CA fibers were investigated in detail. Results showed that all of the cellulose raw materials were esterified within 15 min, and spinning dopes could be obtained by concentrating the CA solutions via vacuum distillation. The XRD, FT-IR, 1H, 13C and HSQC NMR analysis confirmed the successful synthesis of CA. The degree of substitution (DS) of the obtained CA was significantly affected by the degree of polymerization (DP) of cellulose raw materials, which further influenced the viscosity of CA solutions as well as the structural, thermal and mechanical properties of the CA fibers.

In this study, an efficient, reusable, and environmental catalytic system consisting of sugarcane bagasse (an agricultural and sugar mill waste material, SCB) and KI was applied to the cycloaddition of carbon dioxide (CO2) to epoxides or aziridines under mild conditions for the first time. Their catalytic cycloaddition activities were found to be well correlated with the large quantities hydroxyl groups in SCB, which had a synergetic effect with the halide anion of KI. The as-prepared catalytic system also exhibited excellent cycloaddition activities for various epoxide or aziridine substrates as well. Moreover, the catalyst could be recovered and reused multiple times without obvious loss in activity. The present method represents an integrated and ideal green process for the utilization of biomass and “carbon neutral” resources, which has a high potential for large-scale fixation of CO2 into value-added chemicals.Keywords: Carbon dioxide fixation; Cycloaddition reaction; Sugarcane bagasse

Stimulus-responsive hydrogels, which can undergo significant physicochemical changes in response to various physical or chemical stimuli, have drawn wide attention in many fields. In this study, novel photoresponsive hydrogels prepared by free radical copolymerization of xylan-type hemicellulose methacrylate with 4-[(4-acryloyloxyphenyl)azo]benzoic acid (AOPAB) were investigated, which showed multiresponsive behaviors to pH, water/ethanol alternating solutions, and light. The swelling ratios of the prepared hydrogels in distilled water decreased from 9.8 to 2.2 g/g with AOPAB content increase from 2% to 16%. The hydrogel displayed rapid swelling and deswelling performance in water and ethanol alternating solutions. Additionally, under UV irradiation the trans-conformation of azobenzene in the hydrogel would generally convert into the cis-conformation and resulted in the hydrophilic/hydrophobic balance variation of the hydrogel. Therefore, the hydrogel loaded with vitamin B12 (VB12) showed a higher drug cumulative release rate under UV irradiation than that without UV irradiation.

Xylan, which is a widely abundant plant polymer, has been considered as an alternative for film preparation. Up to now, however, xylan films have suffered from brittleness, low mechanical strength, and humidity sensitivity. This paper describes a new and effective strategy to prepare xylan films with high mechanical strength and less moisture-sensitive properties by introducing long carbon chains into the xylan backbone. Furthermore, this work revealed some important details on the relationships between structure (molecular structure, aggregation behaviors, and surface morphology) and properties (film-forming performance, flexibility, tensile strength, and hydrophilicity) of xylan film. It was found that the hydrophobic carbon chains (2-octenylsuccinic anhydride half-ester groups) in the xylan backbone acted as steric hindrance and could effectively prevent xylan chains from aggregation. 2-Octenylsuccinic anhydride (2-OSA) modified xylan (2-OSA-X) demonstrated amorphous structure and had better film-forming performance than the unmodified xylan. 2-OSA-X films were smooth, flexible, and less moisture-sensitive and showed significantly increasing tensile strength at a low degree of substitution.

A novel porous bioadsorbent for metal ion binding (Pd2+ and Cd2+) was successfully prepared from lignocellulosic biomass in ionic liquid by homogeneous succinoylation and sequent chemical cross-linking. The morphology of the bioadsorbent and the interaction between bioadsorbent and metal ions was revealed by scanning electron microscopy and Fourier transform infrared spectroscopy. Results showed that the adsorption mechanism of the bioadsorbent was an ion exchange. A lower dose of cross-linker or higher carboxyl content increased the adsorption capacities of Pd2+ and Cd2+. The adsorption capacities of Pd2+ and Cd2+ remarkably increased as the pH of metal ion solutions increased. The pores in the bioadsorbent greatly favored the diffusion and adsorption of metal ions, and the adsorption equilibrium time was about 50 min. The adsorption of metal ions could be well explained by the Langmuir model, and the maximum adsorption capacities of Pd2+ and Cd2+ were 381.7 and 278.6 mg/g.

A series of amiphiphilic cellulose-based graft copolymers (MCC-g-PLA) with various molecular factors were synthesized in ionic liquid BmimCl and characterized by FT-IR, 1H NMR, 13C NMR, XRD, and TGA. Their solubility in a variety of solvents was compared. The prepared MCC-g-PLA copolymers can self-assemble into spherical nanomicelles (10–50 nm) in aqueous solution. The self-assembly behaviors of the MCC-g-PLA copolymers were systematically investigated by fluorescence probe. Furthermore, the hydrophobic antitumor drug paclitaxel (PTX) was successfully encapsulated into the MCC-g-PLA micelles. The drug encapsulation efficiency and loading content were found to be as high as 89.30% (w/w) and 4.97%, respectively. Results in this study not only suggest a promising cellulose-based antitumor drug carrier but also provide information for property-directed synthesis of the cellulose graft PLA copolymers.

Chemical modification provides an efficient way to obtain novel biomaterials from abundant biomacromolecules. In this case, lauroylated hemicelluloses (LH) with degree of substitutions (DS) between 0.43 and 1.82 were synthesized in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid. The influence of reaction parameters including the molar ratio of lauroyl chloride (LC) to anhydroxylose units in hemicelluloses (0.5:1–3:1), reaction temperature (80–90 °C), and reaction time (15–90 min) was studied. The results indicated that homogeneous modification was successfully conducted and highly substituted hemicelluloses esters were obtained. In comparison, the hemicellulose and LH were characterized by both degradative methods such as thermal analysis (TGA/DTG), and non-degradative techniques such as Fourier transform infrared (FT-IR), 13C nuclear magnetic resonance (NMR) spectroscopy, and scanning electron microscopy (SEM). It was found that a significant degradation of the hemicellulose polymers occurred during lauroylation with the increase of the molar ratio, time, and temperature. The thermal stability of LH was lower that of the native hemicelluloses, and the morphological properties of hemicellulose were significantly changed after the chemical modification.

In this paper, a series of cellulose-based hydrophobic associating polymers were prepared by homogeneous acylation of microcrystalline cellulose with long-chain acyl chlorides including octanoyl, lauroyl, and palmitoly chlorides in the solvent of N,N-dimethylacetamide/lithium chloride (DMAc/LiCl) using pyridine as acid scavenger. Through controlling the chain length of fatty acyl chlorides and the molar ratio of acyl chlorides vs anhydroglucose unit, the hydrophobic cellulose derivatives with degrees of substitution in the range of 0.02–1.75 were successfully obtained. The chemical structures and properties of these hydrophobic derivatives were characterized by elemental analysis, FT-IR, CP/MAS 13C NMR, X-ray diffraction, and the thermogravimetry analysis. It was also found that, the cellulose-based polymers achieved an excellent solubility in organic solvents, such as benzene, methylbenzene, and pyridine, with the introduction of hydrophobic side chain into the cellulose backbone. Furthermore, it was found that these hydrophobic cellulose derivatives could self-assemble into spherical nanoparticles in aqueous solution, which indicates a tremendous potential of applications in pharmaceutical and medical fields.

Chemical modification is the most important method to design novel biopolymer and biomaterials from the abundant and biocompatible hemicelluloses. In this paper, an efficient method to synthesize hemicellulosic derivatives with bifunctional groups was developed by the etherification of hemicelluloses with acrylamide in the butanol/water medium. Varying the reaction condition such as reaction time, reaction temperature, and the amount of acrylamide and so on, the optimized hemicellulosic derivative with a higher total degree of substituent (DS) of 0.92 and with the 0.43 ratio of carbamoylethy groups and carboxyethyl groups was obtained. 13C NMR analysis showed that the etherification occurred preferably at C-3 position of xylose. A significant degradation of the polymers occurred during the etherification. The shear-thinning of the hemicellulosic derivatives became more dramatic. The solution of the hemicellulosic derivatives showed lower viscosity and modulus as compared with the native hemicelluloses, exhibiting a less elastic behavior.

Generation of bioenergy, new functional polymers, or chemicals and biomaterials from hemicelluloses are important uses for biomass. In this paper, a novel functional biopolymer with carbon−carbon double bond and carboxyl groups was prepared by a homogeneous esterification of xylan-rich hemicelluloses (XH) with maleic anhydride in 1-butyl-3-methylimidazolium chloride ([BMIM]Cl) ionic liquid using LiOH as catalyst. The biopolymers with degrees of substitution (DS) between 0.095 and 0.75 were accessible in a completely homogeneous system by changing reaction temperature, reaction time, the dosage of catalyst, and the molar ratio of maleic anhydride to anhydroxylose unit in XH. Results obtained from FT-IR and 13C NMR spectroscopies confirmed the structure of hemicellulosic derivatives with carbon−carbon double bond and carboxyl groups, implying an efficient method to prepare a novel and important functional biopolymer for biomaterials.

This paper is an attempt to investigate the influences of enzyme (laccase) and alkali treatments on the surface lignin of single cellulose fibre. The fibre surface characteristics and the interfacial behaviour of the sisal fibre/phenolic resin composites were also studied by SEM, AFM, XPS. The surface lignin greatly affected the surface physical and chemical properties of single cellulose fibres. The surface lignin concentration was up to 35% for the raw fibre without any treatment, and then it decreased to 24%, 20% and 18% for the fibres with laccase treatment, alkali treatment and laccase/alkali treatment, respectively. The removal of lignin from fibre surface could enhance the interfacial strength of composites, and thus increase the tensile strength and internal bonding strength by 43% and 51%, respectively, for the composites obtained from laccase/alkali treated fibres.

In this study, we investigated the physicochemical properties of the cellulosic preparations obtained from both untreated perennial ryegrass leaves and de-juiced leaves. It was found that treatment at 22 °C with 18% NaOH and 18% KOH for 2 h, and 10% NaOH and 10% KOH for 16 h yielded 28.2%, 28.8%, 22.7%, 23.4%, respectively, of ‘cellulose’ residue from untreated ryegrass leaves and 35.7%, 36.8%, 32.8% and 34.6%, respectively, from the de-juiced leaves. For each cellulosic fraction, the glucose content was 71.6%, 69.6%, 67.8%, 66.7%, 69.7%, 68.6%, 63.9% and 61.7%, respectively. The structure of the cellulose samples was examined using FTIR and CP/MAS 13C NMR spectroscopy and X-ray diffraction. The cellulosic preparations were free of bound lignin except for noticeable amounts of residual hemicelluloses (28.4–38.3%), and had intrinsic viscosities between 275.1 and 361.0 mL/g, along with molecular weights from 144,130 to 194,930 g/mol. This study found that the cellulose samples isolated from both de-juiced ryegrass leaves and the untreated leaves had a much lower percent crystallinity (33.0–38.6%) than that from wood-based fibres (60–70%) and had much shorter fibres (0.35–0.49 mm) than those of either cereal straws, bagasse or wood. In addition, a partial disruption of the hydrogen bonds and microfibrils may occur during the de-juicing process by mechanical activity, which results in a decreased cellulose crystallinity and fibre length. These findings are significant in relation to hydrolysing ryegrass cellulose for bio-ethanol production.